1. Field of the Invention
This invention relates to a streak camera device in which a plurality of streak tubes are driven by the output signal of a single deflecting signal generator, so that the same phenomenon can be analyzed in many aspects.
2. Description of the Background Art
A streak camera is a device for converting time information from a luminous event into spatial information. That is, such a camera can measure the variatin in intensity distribution of a light emission which changes at high speed.
A typical streak camera comprises a streak tube which is an electron tube. In the electron tube, a photocathode and a phosphor screen are arranged, and a pair of deflecting electrodes are disposed therebetween.
When a light beam is applied to the photocathode of the streak tube, the photocathode emits photoelectrons in accordance with changes of the incident light beam over time, thus forming a photoelectron beam which changes with time.
When the photoelectron beam is passed through the electric field formed by the deflecting electrodes while advancing towards the phosphor screen, it is caused to sweep the phosphor screen in one direction. As a result, the change in intensity of the incident light beam appears as a change in luminance of the photoelectron beam in the direction of sweep (i.e., the direction of time axis) on the phosphor screen. This is a so-called "streak image". The streak image is photographed with a camera or detected with a TV (television) camera, so that the distribution of brightness of the output image in the direction of sweep is quantized for measurement of the change in intensity of the light beam. There has been a strong demand for observing an optical phenomenon simultaneously in a plurality of different aspects with such a streak camera.
For instance, in a case where the above optical phenomenon is a luminous phenomenon including a fluorescence having a wide band of wavelengths, in order to measure the attenuation characteristics of respective wavelengths of the fluorescence excited by a laser beam or the like, a method has been proposed and practiced in the art in which a sepctroscope is provided between the streak tube and the light source, and the fluorescence is applied through the spectroscope to the photocathode of the streak tube thereby to disperse the wavelengths. FIG. 7 shows a conventional streak camera including a spectroscope. In FIG. 7, the light beam emitted from the light source 300 is dispersed by the spectroscope 310 and applied to the photocathode 110 of the streak tube 100 in a direction perpendicular to the time axis direction. When the streak tube 100 is operated, the resultant output image is as shown in FIG. 8. As is shown, in the effective output surface, the streak images of various wavelengths (.lambda..sub.1 through .lambda..sub.n) are arranged substantially in parallel with the time axis.
According to the above-described method, in the wavelength region to which the photocathode of the streak tube is sensitive, the attenuation characteristics of a number of fluorescent rays of different wavelengths can be measured.
However, the method cannot be applied to the measurement of the attenuation characteristics of fluorescent rays whose wavelengths are outside the aforementioned particular wavelength region in which the photocathode of the streak tube is sensitive.
In order to overcome this difficulty, the present inventors have used a method in which at least two streak camera devices having streak tubes whose photocathodes are sensitive to different wavelength regions are operated in a parallel mode. However, even if the two streak camera devices are driven by one trigger signal, the output images of the streak camera devices suffer from irregular time fluctuation of several tens of pico-seconds because of the jitters of the respective deflecting signal generators. Therefore, the resultant data are rather difficult to adjust.
Accordingly, an object of this invention is to provide a streak camera device in which the abovedescribed difficulties accompanying a conventional streak camera device have been eliminated. It is a further object of the invention to utilize a plurality of streak tubes to measure one and the same phenomenon in a plurality of aspects.